A362761 Number of nonisomorphic unordered triples of derangements of an n-set.

1, 0, 1, 2, 18, 138, 4642, 211600, 13511246, 1092862024, 109276859229, 13221974420985, 1903936637405380, 321762396855180477, 63065061524052355523, 14189582409276961769144, 3632522968870016652531332, 1049797035002712952582167891, 340133739324533632977813192678

Offset

0,4

Comments

Isomorphism is up to permutation of the elements of the n-set.

Links

Andrew Howroyd, Table of n, a(n) for n = 0..50

Example

The a(3) = 2 nonisomorphic triples of derangements are:
  {(123), (123), (123)},
  {(123), (123), (132)}.

Crossrefs

Column k=3 of A362759.

Cf. A362646, A362760.

Sequence in context: A073512 A005544 A154636 * A216584 A193446 A226733

Adjacent sequences: A362758 A362759 A362760 * A362762 A362763 A362764

Keyword

nonn

Author

Andrew Howroyd, May 02 2023

Status

approved